Turbo Whistle

[dieseldrivingfarmer]

Been able to hear it a little, what can i do to make it more pronounced?

[DmaxMaverick]

Open up your intake with some large metal plumbing and an open type airbox, like AirRaid, AFE, etc. Beware of some of them. If they are open to the engine compartment, they can suck in hot air right off the radiator.

[Chris611]

I removed the cat and muffler as well as a K&N filter. I can really hear the whistle especially in town with with the windows open, when you let off the throttle, you can hear the whistle as the turbo slows down. It's very cool.

[baddiesel]

i went with a 3"downpipe 4"exhaust back lost the kitty and put a k-n cone filter on and my turbo screams

[NH2112]

Put your foot in it harder! :D Seriously, though, the advice given so far is all sound. Let the engine breathe easier and the whistle will get louder.

[Mark Rinker]

In order of effectiveness, in my experience:

1) Heath Turbo-Master over OEM wastegate controls. You can easily dial up more boost = more sound. Wastegate actuation is a 'whoooosh' when the Turbo-Master spring pressure is overcome, rather than the muffled pulsations regulated by the electronic OEM solenoid system; www.heathdiesel.com

2) Cone style air intake filter; (huge increase in VOLUME of sound created by more boost and mechanical wastegate actuation)

3) Exhaust; (Jardine makes an inexpensive 4" system for the 6.5 that whistles like a semi when combined with the aforementioned mods, check out Ebay.)


Add mechanical boost and EGT gauges while you are at it - they are not only useful to monitor critical engine measurements, but fun to watch under different towing and driving conditions. Digital are probably more accurate, but not as fun to monitor, IMO.

[dieseldrivingfarmer]

I know the waste gate controls the exhaust gasses in some way but what exactly is it there for?

[Chris611]

I'm sure others will answer as well, but I believe it is simply there to control the maximum boost level and/or the maximum speed of the turbo. For every part of air you supply, you have to supply fuel (stochiometric (sp) ratio) so my guess is the waste gate is a way of controlling this.

[Shikaroka]

Stoichiometric doesn't really apply to diesels. They just suck as much air as they can, hence no throttle body.

Wastgates are there to control the boost pressure. When a certain pressure is reached, they open up and allow the exhaust gasses to bypass the turbine wheel in the turbo.
The 6.5TD uses vacuum, controlled by the ECU, to pull open the wastegate.
A lot of gas engines use the pressure inside the intake manifold to "blow" open the wastegate.

[MrEdd]

The wastegate stabilizes pressure so the engine isn't getting full boost all the time. Exhaust is constantly running by it, so the only way to keep the turbo from creating boost without shutting the engine down is to wastegate it.

[DmaxMaverick]

A cone type filter is louder because it is not baffled inside an airbox, which is designed by the mfg to muffle the intake noises (not because it flows more).

More boost is not necessarily more sound. The relatively small compresor wheels we deal with on these engines will be most noisy when you find that harmonic "sweet spot". Higher boost will create more tension on the compressor blades, and less harmonic vibration and air chopping. For instance, on my '01, the sound is most pronounced at mid throttle at less than 7 PSI/1800 RPM under heavy load (like take off), and up to 12 PSI/2000 RPM under less loaded highway cruising. While cruising, less than 5 PSI, or more than 12, the sound isn't audible to me.

Keep in mind, not everyone will hear what you hear, and vice versa. The turbo is always making noise. Most of the time, the sound is outside our hearing range, and everyone has different hearing abilities at different frequencies. Changing, or "tuning" your intake, boost and driving habit will move that frequency around. Making changes that work for some may make your turbo completely inaudible to you, or someone else. Someone that has been exposed for a long time to loud machinery may have been desensitized to certain frequencies, which may include the turbo range. If you are hearing your turbo whine now, just opening up the intake will make it louder, but changing the frequency could silence it.

The sound from the exhaust doesn't contribute much, if any, to the whistle you will hear while in the cab. It is the compressor wheel making that noticeable noise. A larger, more free flowing exhaust will enhance the exhaust note, but the combustion pulses and turbine whine usually cancel each other out a little above idle. I recommend a large free flowing exhaust, but not for your listening pleasure, in regards to the whistle. Too much exhaust system volume in the wrong place can/does cause a very annoying (to most people) drone. A muffler or resonator could help/hurt the sound, depending on placement, and your configuration.

If you plan to do all these mods, do one at a time and test it. You'll find that nothing will really improve it until the intake is done correctly.

[arveetek]

I have a 3" downpipe and 4" exhaust with a Kennedy muffler on my '81. I also have a cone-type air filter. My truck sounds as close to a big rig as a V-8 diesel can, at least when I'm pulling a load. The whistle is awesome when I'm pushing 15+ psi, and even when I'm slowing down with no throttle, the turbo chopping the exhaust and the turbine slowing down still sounds cool.

:)

Casey

[Kev-o]

On my old 98 6.5 i bought two exhaust elbows and welded them together and built an aluminum three sided box to catch the cool air from the fender opening and picked up a K&N cone filter! I could barely hear the turbo before that, But after the turbo whistled nicely and you could here the waste gate spewing off the excess! Very easy and affordable MOD!

[dieseldrivingfarmer]

hey Kev-O any chance of a picture of your set up??

[sailun]

I would love to see that intake setup, also. This goes along with my post under EFFECTIVE MODS for MPG. I would appreciate any thoughts or comments/warnings.

[Kev-o]

Truck is sold but i will be doing it to my current ride, a 93 and i will post some pics for you.